Configuration Guide User guide

1156 FastIron Configuration Guide
53-1002494-02
STP feature configuration
The STP group ID identifies the STP instance. All VLANs within an STP group run the same instance
of STP. The master VLAN specifies the bridge STP parameters for the STP group, including the
bridge priority. In this example, each of the devices in the core is configured to be the default root
bridge for a different master VLAN. This configuration ensures that each link can be used for
forwarding some traffic. For example, all the ports on the root bridge for master VLAN 1 are
configured to forward BPDUs for master VLAN spanning tree. Ports on the other devices block or
forward VLAN 1 traffic based on STP convergence. All the ports on the root bridge for VLAN 2
forward VLAN 2 traffic, and so on.
All the portss are tagged. The ports must be tagged so that they can be in both a member VLAN
and the member's master VLAN. For example, port 1/1 – and ports 5/1, 5/2, and 5/3 are in
member VLAN 2 and master VLAN 1 (since master VLAN a contains member VLAN 2).
Here are the commands for configuring the root bridge for master VLAN 1 in figure Figure 151 for
STP per VLAN group. The first group of commands configures the master VLANs. Notice that the
STP priority is set to a different value for each VLAN. In addition, the same VLAN has a different
STP priority on each device. This provides load balancing by making each of the devices a root
bridge for a different spanning tree.
Brocade(config)#vlan 1
Brocade(config-vlan-1)#spanning-tree priority 1
Brocade(config-vlan-1)#tag ethernet 1/1 ethernet 5/1 to 5/3
Brocade(config-vlan-1)#vlan 201
Brocade(config-vlan-201)#spanning-tree priority 2
Brocade(config-vlan-201)#tag ethernet 1/2 ethernet 5/1 to 5/3
Brocade(config-vlan-201)#vlan 401
Brocade(config-vlan-401)#spanning-tree priority 3
Brocade(config-vlan-401)#tag ethernet 1/3 ethernet 5/1 to 5/3
...
Brocade(config-vlan-3601)#vlan 3801
Brocade(config-vlan-3801)#spanning-tree priority 20
Brocade(config-vlan-3801)#tag ethernet 1/20 ethernet 5/1 to 5/3
Brocade(config-vlan-3801)#exit
The next group of commands configures VLAN groups for the member VLANs. Notice that the VLAN
groups do not contain the VLAN numbers assigned to the master VLANs. Also notice that no STP
parameters are configured for the groups of member VLANs. Each group of member VLANs will
inherit its STP settings from its master VLAN.
Set the bridge priority for each master VLAN to the highest priority (1) on one of the devices in the
STP per VLAN group configuration. By setting the bridge priority to the highest priority, you make
the device the default root bridge for the spanning tree. To ensure STP load balancing, make each
of the devices the default root bridge for a different master VLAN.
Brocade(config)#vlan-group 1 vlan 2 to 200
Brocade(config-vlan-group-1)#tag ethernet 1/1 ethernet 5/1 to 5/3
Brocade(config-vlan-group-1)#vlan-group 2 vlan 202 to 400
Brocade(config-vlan-group-2)#tag ethernet 1/2 ethernet 5/1 to 5/3
Brocade(config-vlan-group-2)#vlan-group 3 vlan 402 to 600
Brocade(config-vlan-group-2)#tag ethernet 1/3 ethernet 5/1 to 5/3
...
Brocade(config-vlan-group-19)#vlan-group 20 vlan 3082 to 3282
Brocade(config-vlan-group-20)#tag ethernet 1/20 ethernet 5/1 to 5/3
Brocade(config-vlan-group-20)#exit
The following group of commands configures the STP groups. Each STP group in this configuration
contains one master VLAN, which contains a VLAN group. This example shows that an STP group
also can contain additional VLANs (VLANs not configured in a VLAN group).